In case various kinds of processing such as film forming processing, etching processing, and the like is performed on a to-be-processed object such as silicon wafer, glass substrate, and the like in a vacuum chamber in vacuum atmosphere, it has conventionally been known to perform such processing in a state in which the to-be-processed object is electrostatically attracted by an electrostatic chuck. Here, in performing the processing on the to-be-processed object, there are cases where the to-be-processed object is maintained at a predetermined temperature or the to-be-processed object is maintained at a predetermined temperature which is lower than the room temperature. Then, it is known: to provide a base for supporting a chuck plate which constitutes an electrostatic chuck with a water flow pipe; during processing, to cause cooling water to circulate through this water flow pipe by a cooling water circulation apparatus to thereby cool the base; in this manner to cool the chuck plate and, consequently, the to-be-processed object (see, for example, Patent Document 1).
On the other hand, as a predetermined processing, in case film forming processing is performed by, e.g., sputtering a sputtering target, for the purpose, e.g., of increasing the in-plane uniformity of film thickness distribution or of forming a film on a substrate having a projection/depression shape, it is also known to connect a rotary shaft of a driving motor to a stage on which the to-be-processed object is placed in position. During processing, the stage and consequently the to-be-processed object is processed while rotating it at a predetermined speed (see, for example, Patent Document 2). By the way, in the art described in Patent Document 2, the stage is provided with an electrode for the electrostatic chuck for the to-be-processed object and with a jacket for circulating water. It is thus so arranged that the to-be-processed object is held in a manner to be rotatable and is also capable of being cooled to a predetermined temperature.
However, in each of the methods of the above-mentioned conventional examples in which a liquid such as cooling water and the like is circulated inside the stage as a coolant, despite an attempt to cool the to-be-processed object to a temperature below room temperature, there was a limit in that the to-be-processed object could be cooled down to a temperature of at most about −30° C. In addition, during the processing, should the coolant leak from the stage that is driven for rotation into the vacuum chamber in vacuum atmosphere, not only is the normal processing impaired, but also is the possibility of the processing apparatus itself be damaged. Therefore, it is necessary to employ a complete watertight construction, this bringing about a complication and higher cost of the apparatus.